Offset adjust for moving coil transducer

Abstract

In an electropneumatic transducer, an adjustment spring is used for offsetting the coil in relation to a pneumatic system leakport simply and without hysteresis. One end of the spring supports the suspension element on which the coil is positioned. The offset adjusting spring includes a folded region near the end mounted to the transducer body. A screw mechanism is positioned to compress the sides of the fold toward each other when turned in one direction and allow the sides of the fold to open when turned in the opposite direction. Movements of the sides of the fold flex the adjustment spring, causing the offset to vary adjustably.

What is claimed is: 
     
       1. A coil offset adjusting mechanism for an electropneumatic transducer, comprising: a coil suspension means for supporting a coil;   a lever supporting one end of the coil suspension means;   an offset adjusting spring supporting the other end of the suspension means, the spring having a fold therein; and   an adjusting means for pushing the sides of said fold together when moved in one direction and removing compressive pressure on the sides of said fold when moved in an opposite direction, thereby flexing said suspension means and adjusting the offset of said coil.   
     
     
       2. The mechanism of claim 1, wherein the fold is a "V" shaped region. 
     
     
       3. The mechanism of claim 2, wherein one side of the fold has intermediate portions removed to provide a "dog bone" configuration thereof. 
     
     
       4. The mechanism of claim 1, wherein the side of the fold in the spring adjacent the coil is more flexible than the side of the fold adjacent the adjusting means, thereby permitting the end of the spring supporting the supporting means to flex without moving the adjusting means relative to the fold. 
     
     
       5. The mechanism of claim 1, in which the adjusting means comprises a screw mounted to the transducer to contact one side of the fold. 
     
     
       6. The mechanism of claim 5, wherein the movement of the screw in said one direction closes a pneumatic system leakport and movement of the screw in the other direction opens the leakport, thereby regulating pneumatic pressure in a pneumatic system controlled by the transducer. 
     
     
       7. The mechanism of claim 6, wherein the ends of the adjusting spring are formed so that in their natural position the coil is biased in the direction of closing the leakport. 
     
     
       8. The mechanism of claim 1, in which the adjusting spring is made of a non-magnetically permeable material. 
     
     
       9. The mechanism of claim 8, in which the adjustment spring is made of a beryllium-copper alloy. 
     
     
       10. The mechanism of claim 1, in which the suspension means is made of a non-magnetically permeable material. 
     
     
       11. The mechanism of claim 10, in which the suspension means is made of zinc. 
     
     
       12. An offset suspension system for a moveable coil of an electropneumatic transducer comprising: support means for supporting said coil having one end which is substantially immobilized;   a spring having a pair of ends with a first end being substantially immobilized and a second end connected to the other end of said support means, said spring having a fold between said ends thereof; and   adjusting means for pushing against one side of said fold so as to cause said support means to flex about its immobilized end.   
     
     
       13. The system of claim 12 in which said fold has a V-shaped section. 
     
     
       14. The system of claim 13 in which said adjusting means is a screw mounted to abut one side of said fold.